I did see season 2, but I guess I'm just not remembering it correctly. Wasn't he at one time a real person, but had turned into some kind of spiritual force?

In any case, I think that's what Jacob is. He once was real, but the island, or something, turned him into something more. Whatever he is, I just don't see him as some dude who will eventually end up dead in some shitty L.A. loft.